EMPLOYEE BENEFIT PLANS - AMOUNTS RECOGNIZED IN CONSOLIDATED BALANCE SHEETS (DETAILS) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011
Pension and Other Postretirement Defined Benefit Plans, Liabilities [Abstract]
Accrued benefit liability-long term	$ 489	$ 463
Qualified Defined Benefit [Member]
Pension and Other Postretirement Defined Benefit Plans, Liabilities [Abstract]
Accrued benefit liability-current	0	0
Accrued benefit liability-long term	335	306
Total liability recognized	335	306
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Prior service cost (credit)	(15)	(15)
Net loss	695	613
Amount recognized in AOCI (pretax)	680	598
Nonqualified Defined Benefit [Member]
Pension and Other Postretirement Defined Benefit Plans, Liabilities [Abstract]
Accrued benefit liability-current	2	2
Accrued benefit liability-long term	40	41
Total liability recognized	42	43
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Prior service cost (credit)	0	0
Net loss	9	12
Amount recognized in AOCI (pretax)	9	12
Postretirement Medical Benefits [Member]
Pension and Other Postretirement Defined Benefit Plans, Liabilities [Abstract]
Accrued benefit liability-current	4	4
Accrued benefit liability-long term	113	116
Total liability recognized	117	120
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Prior service cost (credit)	2	2
Net loss	(15)	(4)
Amount recognized in AOCI (pretax)	$ (13)	$ (2)